Does the Effectiveness of a Medicine Copay Voucher Vary by Baseline Medication Out-Of-Pocket Expenses? Insights From ARTEMIS

BACKGROUND: Persistence to P2Y12 inhibitors after myocardial infarction (MI) remains low. Out-of-pocket cost is cited as a factor affecting medication compliance. We examined whether a copayment intervention affected 1-year persistence to P2Y12 inhibitors and clinical outcomes. METHODS AND RESULTS: In an analysis of ARTEMIS (Affordability and Real-World Antiplatelet Treatment Effectiveness After Myocardial Infarction Study), patients with MI discharged on a P2Y12 inhibitor were stratified by baseline out-of-pocket medication burden: low ($0–$49 per month), intermediate ($50–$149 per month), and high (≥$150 per month). The impact of the voucher intervention on 1-year P2Y12 inhibitor persistence was examined using a logistic regression model with generalized estimating equations. We assessed the rates of major adverse cardiovascular events among the groups using a Kaplan–Meier estimator. Among 7351 MI-treated patients at 282 hospitals, 54.2% patients were in the low copay group, 32.0% in the middle copay group, and 13.8% in the high copay group. Patients in higher copay groups were more likely to have a history of prior MI, heart failure, and diabetes compared with the low copay group (all P<0.0001). Voucher use was associated with a significantly higher likelihood of 1-year P2Y12 inhibitor persistence regardless of copayment tier (low copay with versus without voucher: adjusted odds ratio [OR], 1.44 [95% CI, 1.25–1.66]; middle copay: adjusted OR, 1.63 [95% CI, 1.37–1.95]; high copay group: adjusted OR, 1.41 [95% CI, 1.05–1.87]; P interaction=0.42). Patients in the high copay group without a voucher had similar risk of 1-year major adverse cardiovascular events compared with patients in the high copay group with a voucher (adjusted hazard ratio, 0.89 [95% CI, 0.66–1.21]). CONCLUSIONS: Medication copayment vouchers were associated with higher medication persistence at 1 year following an MI, regardless of out-of-pocket medication burden.